It’s no secret that the habitat of our more Northern creatures is declining due to increases in overall temperature. It is also true that in the history of the earth, there have been closings and openings of waterways and formation and then subsequent retreat of glacial ice sheets; however, it is the rate at which Arctic ecosystems are now changing that is of concern (Root et al. 2003, Overpeck et al. 2005, Walsh 2008). Research is now being done to explore what the effects of melting ice and loss of habitat are on Arctic species populations.

One such paper was written by the Ecological Society of America (Moore and Huntington in 2008, Ecological Applications pp. S157-S165). In this paper, the authors explore how recent changes in Arctic climate may challenge the adaptive capability of more northern adapted species, such as some species of whales, walrus seals and polar bears. Continue reading

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Fig Wasp and Nematode Interaction:

This 1993 David Herre paper discusses how increased opportunities for parasite transmission will promote the evolution of increased virulence. This is in contrast to the usual assumption that parasites and other disease-producing organisms tend to evolve benign relationships with their hosts.

The model system used to demonstrate this point is the natural history of fig-pollinating wasps and the nematodes that parasitize these wasps. This system is useful because the foundress wasps that remain within the fig fruit may be counted and their lifetime reproductive success can be measured.

In Herre’s experiments, 11 species of Panamanian fig wasps were studied. The nematode virulence of different population structures (i.e. vertical vs. horizontal transmission) were determined by comparing the relative reproductive success of infected versus uninfected single foundress wasps. It was found that the nematode species with the greatest estimated virulence were associated with host wasp species that are characterized by population structures providing the most frequent opportunities for horizontal transmission of their parasites. This is evidence that counters the theory that parasites and other disease-producing organisms tend to evolve benign relationships with their hosts over time.

The links provided below explore the fig-wasp life cycle in more detail.